Conversion of carbonaceous substances, tars, mineral oils, and the like into more valuable products



March 24, 1936. Q KRAUCH EVAL 42,035,133

CONVERSION oF cARBoNAcEoUs sUBsTANoEs, TARs, MINERAL OILS AND THE LIKE INTO MORE NALUABLE PRODUCTS Filed May 31, 1927 Patented Mar. 24, 1936 CONVERSION OF CARBONACEOUS SUB- STANCES, TARS, MINERAL OILS, AND THE A LIKE INTO MORE 'VALUABLE PRODUCTS Carl' Krauch, Ludwigshafen-on-the-Rhine, and Mathias Pier, Heidelberg, Germany, assignors, by mesne assignments, to Standard-I. G. Company, Linden, N. J., a corporation `of Delaware Application May 31, 1927, Serial- No. 195,582 In Germany June 1, 1926 11 caims. (c1. 19e-5s) It is known that hydrocarbons, for instance mineral oils, are decomposed by distillation at higher temperatures, with the formation, on the one hand, of substances of a lower boiling point and gases, and on the other hand, of carbon and substances having a higher boiling point than the initial materials. This action is made use of in practice in the well-known cracking process for the production of benzine from mineral oils.

In the known processes of this kind, however, the yields are comparatively small, because numerous less valuable and undesired by-products are produced.

'Ihe yields in liquid hydrocarbons of low boil- ]5 ing point are also sometimes unsatisfactory when carrying out the operation in the presence of hydrogen, even when working under pressure, and especially when carrying out the process on a large industrial' scale, and moreover troubles may occur in the course of the operation.

We have now found that excellent yields, especially in hydrocarbons of low boiling point are obtained, if carbonaceous liquids, by which are understood pastes with coal and other solid fuels,

tars, mineral oils, their distillation and conversion products and residues and the like, are subjected chiefly in the liquid state to a treatment by heat in the presence of catalysts and under any desired pressure, and the products thus obtained are passed in the vaporous and preferably in a superheated state over catalysts. By this manner of Working it is possible to carry out the heat treatment of the initial substances in a liquid state at lower temperatures than are required in the usual cracking or destructive hydrogenation processes for the production of products of low boiling point whether carried `out with or without pressure. The operation at lower temperatures has the particular advantage, that the deposition of carbon and the formation 0f gases, for instance of methane, are remarkably diminished. Either the first stage of heat treatment or the second stage of treating the p referably superheated vapors or both operations may be carried out, if so desired, in the presence of inert gases or of gases participating in the reaction, or mixtures of such, especially inthe presence of hydrogen or gases giving off hydrogen. Instead of, or besides hydrogen, also water vapor, carbon dioxid, carbon monoxid, nitrogen or gases such as ammonia, which act catalytically, may be employed as gases to be added..`

The process can be carried out at any desired pressure, but particularly advantageous results are obtained when working with streaming hydrogen in excess, that means under a high par- 4 tial pressure, and employing elevated pressure.

In the first stage of the process the temperature employed will generally range between about 300 and 500 C.; it may, however, in some cases 5 also be outside the said range, as it depends on the nature of the initial material, especially on its contents in asphaltic materials, and on the other conditions of working. The temperature employed in the second stage depends on the nal0 ture of the intermediate products to be treated; it will generally be about from 50 and 100 C. higher than that employed in the first stage of the process. It is to be understood that the temperature employed with one kind of initial mal5 terial in the first stage may be higher than those employed in the second stage with another kin of initial material.

carry out the second stage of the process under another pressure than the first stage. 25

The catalysts should comprise one or more elements of the second to the eighth group of the periodic system or compounds thereof. 'Ihey may be of metallic or non-metallic; nature, and may be employed in the form of smooth surfaces, 30 or of wires, filings, porous pieces or in the form of powder, and with or without supports. As examples of metals we mention molybdenum, tungsten, aluminium, cobalt, and alloys especially of the heavy metals, for instance, highly al- '35 loyed, if necessary thermically pretreated steels; other suitable catalysts are for example tungstic acid, molybdic acid, aluminium hydroxid, bauxite, active charcoal, alderwood-charcoal which has been thoroughly glowed out, pine wood- ,i charcoal, titanic acid aluminium silicates, manganous oxid, uranium aluminate silicate, mixtures of reduced copper and iron oxids, diatomaceous earth, pumice stone and the like. The catalysts hereinbefore mentioned will be em- 45 ployed in either stage of the process.

In the first stage of the process in which the initial substances are treated mainly in the liquid state, the catalysts are preferably added to the initial materials in the form of powder, whereas 50 porous contact bodies are preferably employed in the second stage, which is the treatment in the vapor state of the products obtained.

It is advisable in carrying out the process according to the present invention to keep the hot 55 tice, but the invention as would give rise to a depositionA of carbon and to the formation of methane. terial for the walls of the reaction vessel should be so chosen as to be resistant to sulfur and oxygen,

`for instance the same may be made of or lined according to the present invention. Fresh gas is introduced through a valve A' by way of a pipe B into a pipe C through which the carbonaceous liquids to be treated are passed. Gases which have already passed through the whole process are returned in circulation and introduced into the pipe C at S'. The mixture is passed through a coil F arranged in a preheater G and is introduced at'E into a stirring vessel J containing a catalyst, where the treatment essentially in the liquid phase takes place. The products are taken on from the said vessel at H and introduced into a reaction vessel containing a catalyst at Kin which vessel the reaction is carried out in the vapor state.V The reaction product is then passed through the pipe L to a condemer M where the greater portion ofthe liquid products are recovered and the gases are then further passed througha stripping vessel N where the rest of the liquid products are' recovered. The gases emerging from the stripping vessel at O are passed through a circulatory pump P and are then returned to the process at S'.

'I'he following example will further illustrate how our invention may be carried out in pracis not limited to this example. "i v Example Preheated lignite tar is continuously forced into a vertically arranged high pressure reaction vessel, the hot parts of which are lined with aluminium. The lower part of the vessel is maintained at about 420 C. Hydrogen in excess is passed at 200 atmospheres through the liquid reaction mass containing from 1 to 5 per cent of Florida earth in a fine state of division, while stirring. 'I'he vapors thus produced, which contain comparatively little benzine, and consist chiefly of middle oils, are immediately passed in the upper portion of said reaction vessel at 480 C. over a porous catalyst prepared by reducing a mixture of molybic acid and' zinc oxid which is permanently arranged in the apparatus. On cooling the gases and vapors leaving the reaction vessel, a product containing about per cent of benzine is` obtained in a brisk operation, by a single treatment'of the initial material without the formation of coke or a substantial formation of methane.

v The hydrogen is advantageously pumped round in a circulatory system, the consumed portion being made up for by the addition of fresh gas. Instead of carrying out the catalytic treatment of the vapors'immediately after the first stage treatmentin the same reaction vessel, the intermediate products may be-'condensed and subjected separately to the treatment described in a second apparatus. Other tars, pitches, petroleum residues, pastes with coal, lignite, and the like, in hydrocarbons or other liquid media maybe treated in the same way as lignite tar an'dfwith similar results.

Further, the ma.-

zone of the apparatus free from such substances In our copending application Ser. No. 86,646,

led 'February 6th, 1929 we-have disclosed, among other things, a two-stage processfor converting carbonaceous materials of the nature of solid and liquid fuels, distillation and extraction products thereof, into low boiling oils by a two-stage process. Example 9 of that application discloses a process accordingto which lignite, alone or mixed with oil, -is treated with hydrogen under a pressure of 200 atmospheres and at a temperature of about 480 C. and the products resulting from this treatment are passed in the vapor phase over calcium carbonate, for which a catalyst of morepreeious character can be substituted, under the saine pressure as used in the first stage .and at a temperature ranging from 500 tov 550 C. The disclosure of this particular'type of a twostage process is common to Ser. No. 86,646 and this application. This particular procedure is covered vby the claims of this application. To that extent, therefore, this application is a continuation in part of Ser. No. 86,646.

What we claim is:

1. The process of converting a substance of the nature of coal tar into lower boiling hydrocarbons which comprises subjecting the said tar in the liquid phase to a heat-treatment at a temperature of about 420 C., under a pressure of about 200 atmospheres and in the presence of hydrogen and then passing the vapors evolved from said tar at a temperature of about 480 C. and under substantially the same pressure over a catalyst comprising molybdic acid and zinc oxide.

2. A combination process for producing valuable low boiling hydrocarbons from higher boiling oils capable of several stages 'of conversion, comprising the destructive hydrogenation of such oil in the liquid phase at a relatively low destructive hydrogenation temperature whereby oil of low boiling and intermediate boiling fractions containing comparatively littlei benzines is produced,

separating such fractions and then converting theintermediate fractions in the vapor phase into a low boiling distillate consisting chiefly of benzines at a destructive hydrogenation temperature from 50 to 100 C. higher than the temperature used in the rst stage in the presence of a catalyst capable of promoting the cracking of hydrocarbons.

. 3. Process according to claim 2 in which the rst step is accomplished at a temperature within the approximate range of 300 to 500 C.

y 4. Process according to claim 2, in which destructive hydrogenation and conversion of the intermediate hydrogenation product to'low bolling hydrocarbons are carried out under the iniluence of catalytic materials immune to sulfur poisoning.

5. An improved process for producing valuable low boiling distillates from heavier hydrocarbon oil capable of several stages of conversion, which comprises subjecting such oil in the lliquid phase to destructive hydrogenation in the presence of a sulfactive catalyst in a primary zone under pressure in excess of 20 atmospheres and at temperature of 300 C. to about 500 C. for a time sumcient to convert a part of the oil into naphtha and a part thereof into heavier intermediate oil, separating such fractions, and then subjecting the heavier intermediate oil to destructive hydrogenation in vapor phase over a sulfactive catalyst in a secondary zone at a temperature from 50 to 100 C. above that used in the primary zone and between the limits of 350 and 600 C.

6. An improved process for obtaining' valuable low boiling oils from heavier hydrocarbon oils,

residues and the like capable of several stages of conversion, which comprises subjecting the heavy oil to distillation in presence of hydrogen and a sulfactive catalyst, under pressure in excess of 100 atmospheres and at temperatures from 300 to 500 C. whereby naphtha and a heavier intermediate fraction are obtained as distillates, separating these fractions, and .then treating the heavier oil in the vapor phase over a sulfactive catalyst with hydrogen under pressure in excess of 100 atmospheres and at a temperature from about 50 to 100 C. higher than that used in the rst stage, whereby it is converted largely into low boiling oil.

'7. The process of converting liquid hydrocarbons capable of several stagesof conversion into lower boiling hydrocarbons which comprises subjecting the said hydrocarbons, chiefly in the liquid state, to atemperature between 300 and 500 C. until the said initial material is substantially completely converted chieiiy into a lower boiling oil containing comparatively little benzine and then passing the resulting lower boiling products in the vapor state at a temperature which is higher than the temperature used in the first stage by from 50 to 100 C. over a catalyst comprising at least one metal selected from groups 3 to 8 of the periodic system capable of promoting the cracking of the hydrocarbons.

8. The process of converting liquid hydrocarbons capable of several stages of conversion into lower boiling hydrocarbons which comprises subjecting the said hydrocarbons, chiefly in the liquid state, to a temperature between 300 and 500 C. until the said initial material is substantially completely converted chiefly into a lower boiling oil containing comparatively little benzine and then passing the resulting lower boiling products in the vapor state at a temperature which is higher than the temperature used in the rst stage by from 50 to 100 C. over a catalyst comprising at least one metal selected from groups 3 to 8 of the periodic system capable of promoting the cracking of the hyd: ocarbons, hydrogen being employed in at least one of the two stages of the process.

9. The process of converting liquid hydrocarbons capable of several stages of conversion into lower boiling hydrocarbons which comprises subjecting the said hydrocarbons, chieily in the liquid state, to a temperature between 300 and 500 C. until the said initial material is substantially completely converted chiey into a lower boiling oil `containing comparatively little benzine and then passing the resulting lower boiling products in the vapor state at'a temperature which is higher than the temperature used in the rst stage by from 50 to 100 C. over a catalyst comprising at least one metal selected from groups 3 to 8 of the periodic system capable of promoting the crackving of the hydrocarbons, both stages being carried out under a high pressure and hydrogen being present in at least one of the two stages.

10.4 A process as dened in claim 2 wherein the catalyst employed in the second stage comprises at least one metal selected from groups two to eight of the periodic system.

11. A process for the destructive hydrogenation of hydrocarbon oil which comprises introducing said oil into a reaction zone maintained under temperature and pressure conditions adequate to eiect liquid phase conversion and hydrogenation therein, introducing suiicient hydrogen-containing gas directly into the liquid oil in said reaction zone to eect hydrogenation thereof, removing vaporous reaction products from said zone and introducing the same into a secondary reaction zone and reacting the vaporous reaction products in said secondary zone with hydrogen-containing gas to eiect further hydrogenation thereof.

. CARL KRAUCH. MA'I'HIAS PIER. 

